Update README with PR Summary

[glenn-jocher]

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Introducing AI-powered summaries for PRs using OpenAI GPT-4!

📊 Key Changes

• Updated the format.yml workflow to include comments detailing what each option does.
• Integrated a feature to generate AI-powered PR summaries using OpenAI GPT-4.
• Refined the README.md documentation to reflect new features and workflow file name.
• Adjusted the workflow triggers to respond to opened, closed, and synchronized PRs.

🎯 Purpose & Impact

• 📝 Providing clearer descriptions in the workflow file enhances understanding of its functionality.
• ⏰ AI-generated PR summaries aim to improve code review efficiency and clarity.
• 📚 Improved documentation helps users implement and customize the Ultralytics Actions more easily.
• 🔄 Responsive workflow to PR changes ensures better automation and management of repository code and documentation.